1. Field of the Invention
The present invention relates to imaging systems. More specifically, the present invention relates to systems and methods for nonuniformity correction for imaging systems.
2. Description of the Related Art
Imagers in various spectral bands are used in a variety of applications, both commercial and military. Unfortunately, certain imagers exhibit a significant signal rolloff toward the edges of the display. This rolloff is due to a responsivity distortion in which the gain falls off (attenuation increases) as a function of spatial location (distance from center) within one or more optical components. The rolloff has been labeled as the “porthole” effect and degrades image presentation as well performance. The resulting image presentation is degraded due to the distracting center circular region of the display that appears brighter than the edges. Performance is also degraded due to the fact that sensor signal processing wastes display dynamic range on the rolled off signal output from center to edge.
The porthole effect is due to optical distortion. Optical approaches to the correction of such optical distortion have been somewhat expensive to implement. In addition, the optical approaches do not allow for an inexpensive retrofit of existing systems in the field.
Hence, a need exists in the art for an electronic system or method for improving the performance of imagers. Specifically, a need exists in the art for an electronic system or method for improving the responsivity distortion of imagers.